Java Literals

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By literal we mean any number, text, or other information that represents a value.

Java Literals

By literal we mean any number, text, or other
information that represents a value. This means what you type is what you get.
We will use literals in addition to variables in Java statement. While writing a
source code as a character sequence, we can specify any value as a literal such
as an integer. This character sequence will specify the syntax based on the
value's type. This will give a literal as a result. For instance

int month = 10;

In the above statement the literal is an integer value
i.e 10. The literal is 10 because it directly represents the integer value.

In Java programming language there are some special
type of literals that represent numbers, characters, strings and boolean values.
Lets have a closer look on each of the following.

Number LiteralsNumber literals is a sequence of digits and a suffix as L. To represent the
type as long integer we use L as a suffix. We can specify the integers either in
decimal, hexadecimal or octal format. To indicate a decimal format put the left
most digit as nonzero. Similarly put the characters as ox to the left of
at least one hexadecimal digit to indicate hexadecimal format. Also we can indicate the
octal format by a zero
digit followed by the digits 0 to 7. Lets tweak the table below.

659L

Decimal integer literal of type long integer

0x4a

Hexadecimal integer literal of type integer

057L

Octal integer literal of type long integer

Character LiteralsWe can specify a character literal as a single printable character in a pair
of single quote characters such as 'a', '#', and '3'.
You must be knowing about the ASCII character set. The ASCII character set
includes 128 characters including letters, numerals, punctuations etc. There are
few character literals which are not readily printable through a keyboard. The
table below shows the codes that can represent these special characters. The letter d
such as in the octal, hex etc represents a number.

Escape

Meaning

\n

New line

\t

Tab

\b

Backspace

\r

Carriage return

\f

Formfeed

\\

Backslash

\'

Single quotation mark

\"

Double quotation mark

\d

Octal

\xd

Hexadecimal

\ud

Unicode character

It is very interesting to know that if we want to specify a single quote, a backslash, or a nonprintable character
as a character literal use an escape sequence. An escape sequence uses a
special syntax to represents a character. The syntax begins with a single backslash character.
Lets see the table below in which the character literals use Unicode escape
sequence to represent printable and nonprintable characters both.

'u0041'

Capital letter A

'\u0030'

Digit 0

'\u0022'

Double quote "

'\u003b'

Punctuation ;

'\u0020'

Space

'\u0009'

Horizontal Tab

Boolean Literals
The values true and false are also treated as literals in Java programming. When
we assign a value to a boolean variable, we can only use these two values.
Unlike C, we can't presume that the value of 1 is equivalent to true and 0 is
equivalent to false in Java. We have to use the values true and false to
represent a Boolean value. Like boolean chosen = true;
Remember that the literal true is not represented by the quotation marks around it.
The Java compiler will take it as a string of characters, if its in quotation
marks.Floating-point literalsFloating-point numbers are like real numbers in mathematics, for example,
4.13179, -0.000001. Java has two kinds of floating-point numbers: float and
double. The default type when you write a floating-point literal is double.

Type

Size

Range

Precision

name

bytes

bits

approximate

in decimal digits

float

4

32

+/- 3.4 * 1038

6-7

double

8

64

+/- 1.8 * 10308

15

A floating-point literal can be denoted as a
decimal point, a fraction part, an exponent (represented by E or e) and as an
integer. We also add a suffix to the floating point literal as D, d, F or
f. The type of a floating-point literal defaults to double-precision floating-point.The following floating-point literals represent double-precision floating-point and floating-point values.

6.5E+32 (or 6.5E32)

Double-precision floating-point literal

7D

Double-precision floating-point literal

.01f

Floating-point literal

String LiteralsThe string of characters is represented as String literals in Java. In Java
a string is not a basic data type, rather it is an object. These strings are not
stored in arrays as in C language. There are few methods provided in Java to
combine strings, modify strings and to know whether to strings have the same value.
We represent string literals as
String myString = "How are you?";
The above example shows how to represent a string. It consists of a series of characters inside double quotation
marks.

Strings can include the character escape codes as well,
as shown here:
String example = "Your Name, \"Sumit\"";
System.out.println("Thankingyou,\nRichards\n");

Null Literals
The final literal that we can use in Java programming is a Null literal. We
specify the Null literal in the source code as 'null'. To reduce the number of references to an object,
use null literal. The type of the null literal is always null. We typically assign null literals to object reference variables.
For instance

s = null;

An this example an object is referenced by s. We reduce the number of references
to an object by assigning null to s. Now, as in this example the object is no
longer referenced so it will be available for the garbage collection i.e. the
compiler will destroy it and the free memory will be allocated to the other
object. Well, we will later learn about garbage collection.